Excerpts from Books and Wikipedia
"In late 1807, when the Portuguese refused to close their ports and declare war on their old ally, England, Napoleon invaded Portugal. The Portuguese royal family fled, accompanied by a glittering entourage of nobles and government officials, swarms of servants and courtiers—over ten thousand people, as well as the royal treasury— sailing from Lisbon only hours before Napoleon’s troops arrived in the Portuguese capital. British warships were on hand to escort the royal flotilla and, most especially, Prince João (who exercised power in the name of the queen, his demented mother) to Brazil. For more than a decade, João made his court in Rio de Janeiro, safely outside the reach of Napoleon." [Born in Blood & Fire: A Concise History of Latin America, 4th Ed., p. 99]